U.S. patent application number 12/202402 was filed with the patent office on 2010-03-04 for method for mounting an led module on a support.
This patent application is currently assigned to Fu Zhun Precision Industry (Shen Zhen) Co., Ltd.. Invention is credited to You-Xue Liu, Ci-Jin Mo, Qing-Hai Ruan.
Application Number | 20100053962 12/202402 |
Document ID | / |
Family ID | 41725205 |
Filed Date | 2010-03-04 |
United States Patent
Application |
20100053962 |
Kind Code |
A1 |
Mo; Ci-Jin ; et al. |
March 4, 2010 |
METHOD FOR MOUNTING AN LED MODULE ON A SUPPORT
Abstract
A method for mounting an LED module on a support comprises
providing an LED module comprising a printed circuit board and
multiple LEDs mounted on the printed circuit board, a support and a
plurality of fasteners, each fastener comprising a head, a pole
extending downwardly from a bottom of the head, and a plurality of
teeth protruding downwardly from the bottom of the head and
surrounding the pole, extending the fasteners through the printed
circuit board of the LED module into the support, rotating each
fastener such that the teeth thereof scrape insulating layers off a
metal substrate of the printed circuit board, whereby a top face of
the substrate is exposed and in direct contact with the teeth of
the fasteners.
Inventors: |
Mo; Ci-Jin; (Shenzhen City,
CN) ; Liu; You-Xue; (Shenzhen City, CN) ;
Ruan; Qing-Hai; (Shenzhen City, CN) |
Correspondence
Address: |
PCE INDUSTRY, INC.;ATT. Steven Reiss
288 SOUTH MAYO AVENUE
CITY OF INDUSTRY
CA
91789
US
|
Assignee: |
Fu Zhun Precision Industry (Shen
Zhen) Co., Ltd.
Shenzhen City
CN
Foxconn Technology Co., Ltd.
Tu-Cheng
TW
|
Family ID: |
41725205 |
Appl. No.: |
12/202402 |
Filed: |
September 1, 2008 |
Current U.S.
Class: |
362/249.01 |
Current CPC
Class: |
H05K 1/056 20130101;
H05K 3/0061 20130101; H05K 3/28 20130101; H01R 4/26 20130101; H05K
2201/10106 20130101; H05K 2201/10409 20130101; F21V 21/002
20130101; H01R 13/6485 20130101 |
Class at
Publication: |
362/249.01 |
International
Class: |
F21V 21/002 20060101
F21V021/002 |
Claims
1. A method for mounting an LED module on a support, comprising 1)
providing an LED module having a printed circuit board and a
plurality of LEDs mounted thereon, a support, and an electrically
conductive fastener, the printed circuit board having a metal
substrate and an insulating layer formed on a top face of the
substrate; 2) removing a corresponding part of the insulating layer
from the substrate to expose the top face of the substrate; and 3)
extending the fastener through the printed circuit board into the
support, wherein an end of the fastener establishes electrical
communication with a top face of the insulating layer and the top
face of the substrate.
2. The method for mounting an LED module on a support as claimed in
claim 1, wherein step 2) is implemented by milling the
corresponding part of the insulating layer off the substrate.
3. The method for mounting an LED module on a support as claimed in
claim 1, wherein step 2) is simultaneously implemented with step 3)
by scraping the corresponding part of the insulating layer off the
substrate with the fastener when the fastener is extended through
the printed circuit board into the support.
4. The method for mounting an LED module on a support as claimed in
claim 3, wherein the fastener comprises a head, a pole extending
downwardly from the head, and a plurality of teeth protruding
downwardly toward the support, the plurality of teeth scraping the
corresponding part of the insulating layer from the substrate in
step 2).
5. The method for mounting an LED module on a support as claimed in
claim 4 further comprising step 4) continuously scraping the
substrate with the plurality of teeth of the fastener after step
3).
6. The method for mounting an LED module on a support as claimed in
claim 5, wherein a substrate portion scraped off by the plurality
of teeth of the fastener has a thickness of 0.2 mm.
7. The method for mounting an LED module on a support as claimed in
claim 4, wherein the fastener is made integrally.
8. The method for mounting an LED module on a support as claimed in
claim 4, wherein the fastener comprises a screw and an annulus
detachably sleeved on the screw, the head and the pole together
constituting the screw, and the teeth being formed from the
annulus.
9. The method for mounting an LED module on a support as claimed in
claim 4, wherein each of the plurality of teeth is triangular.
10. The method for mounting an LED module on a support as claimed
in claim 1, wherein a through hole is defined through the printed
circuit board, the corresponding removed part of the insulating
layer being annular and surrounding the through hole.
11. A method for mounting an LED module on a support, comprising 1)
providing an LED module comprising a printed circuit board and a
plurality of LEDs mounted on the printed circuit board, the printed
circuit board comprising a metal substrate and an insulating layer
formed on a top face of the substrate; 2) providing a support which
is grounded; 3) providing a plurality of electrically conductive
fasteners each comprising a head, a pole extending downwardly from
a bottom of the head, and a plurality of teeth extending downwardly
and surrounding the pole; 4) extending the plurality of fasteners
through the printed circuit board and into the support; and 5)
rotating the plurality of fasteners such that the plurality of
teeth thereof scrape portions of the insulating layer off the top
face of the substrate of the printed circuit board, whereby the
plurality of fasteners electrically connects with a top face of the
remaining insulating layer and the top face of the substrate.
12. The method for mounting an LED module on a support as claimed
in claim 11, wherein the plurality of teeth continues to scrape the
top face of the substrate after step 5) to reach a lower level 0.2
mm from the top face of the substrate of the printed circuit
board.
13. The method for mounting an LED module on a support as claimed
in claim 11, wherein each of the plurality of fasteners is made
integrally.
14. The method for mounting an LED module on a support as claimed
in claim 11, wherein each of the plurality of fasteners comprises
two mutually detachable parts, one comprising the head and the
pole, and the other comprising a ring and the plurality of teeth
formed from the ring.
15. The method for mounting an LED module on a support as claimed
in claim 11, wherein each of the plurality of teeth has a sharp
extremity end projecting toward the support.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a light emitting diode
(LED) module on a support, and more particularly to a method for
mounting an LED module on a support which can effectively prevent
static electricity accumulation on the LED module.
[0003] 2. Description of Related Art
[0004] LEDs have been available since the early 1960's. Because of
their relatively high light-emitting efficiency, LED usage has
increased in popularity in a variety of applications, such as
residential, traffic, commercial, and industrial settings. In such
applications, for sufficient light output, a plurality of LED
modules is incorporated in a housing which supports mounting of the
LED modules thereon, and also as a heat sink dissipating heat
generated by the LED modules to an atmosphere ambient. Generally,
most conventional LED modules are silicon printed circuit boards
with multiple LEDs fixed thereon.
[0005] Recently, there has been proposed an LED module substituting
a metal printed circuit board for the conventional board, to
improve heat dissipation therefrom, thereby allowing increased
density of arrangement of the LEDs on the printed circuit board,
thus enhancing overall light output per LED module. The metal
printed circuit board requires electrical insulation from the LEDs,
preventing electrical communication therebetween. Among the many
attempts at insulating the metal printed circuit board from the
LEDs, one example thereof sequentially forms a first insulating
layer, an electrically conductive layer, and a second insulating
layer on the metal printed circuit board. The first insulating
layer insulates the metal printed circuit board from the
electrically conductive layer, which is directly connected to
electrode leads of the LEDs, supplying current thereto, the second
insulating layer overlays the electrically conductive layer to
prevent contact between the electrically conductive layer and other
electrical terminals, which may disturb normal operation of the
LEDs if in electrical connection with the electrically conductive
layer. A plurality of screws with insulating washers sleeved
thereon extends through the metal printed circuit board to thereby
attach the LED modules to the housing.
[0006] When the LED module is tested under a high voltage value by
a testing device for determining electrical parameters thereof, or
after being utilized for a long period as a light source in an LED
lamp, there arises a probability that static electricity may be
unexpectedly generated on an external surface of the second
insulating layer. Since the washers, often of electrically
insulating plastic material, are present between the screws and the
external surface of the second insulating layer, the external
surface of the second insulating layer can be substantially
insulated from the screws. The static electricity on the external
surface of the second insulating layer cannot be evacuated by the
screws to ground, but will remain and accumulate gradually. A
significant electrostatic discharge (ESD) may therefore occur in
the LED module when accumulated static electricity reaches a
critical value, and current may flow into the LEDs from the
electrostatic discharge, resulting in malfunction or damage to the
LEDs.
[0007] What is needed, therefore, is a method for mounting an LED
module on a support which can overcome the described
limitations.
SUMMARY OF THE INVENTION
[0008] A method for mounting an LED module on a support comprises
providing an LED module, a support and a plurality of fasteners,
each comprising a head, a pole extending downwardly from a bottom
of the head, and a plurality of teeth protruding downwardly from
the bottom of the head and surrounding the pole, inserting the
fasteners through a printed circuit board of the LED module into
the support, rotating each fastener to cause the teeth thereof to
scrape parts of insulating layers off a metal substrate of the
printed circuit board, whereby a top face of the substrate is
exposed and in direct contact with the teeth of the fastener.
Accordingly, an electrically conducting pathway between a top face
of the insulating layers and the top face of the substrate is
formed via the fasteners, and electrostatic electricity generated
on the top face of the insulating layers can flow to the support
through the pathway. Therefore, malfunction or damage to the LEDs
by electrostatic discharge is avoided.
[0009] Other advantages and novel features of the present invention
will become more apparent from the following detailed description
when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Many aspects of the present apparatus can be better
understood with reference to the following drawings. The components
in the drawings are not necessarily drawn to scale, the emphasis
instead being placed upon clearly illustrating the principles of
the present apparatus. Moreover, in the drawings, like reference
numerals designate corresponding parts throughout the several
views.
[0011] FIG. 1 is an assembled, top view of an LED module, two
screws and a support fabricated by applying a method in accordance
with an embodiment of the present invention.
[0012] FIG. 2 is an exploded, cross-sectional view of FIG. 1 taking
along line II-II, wherein the two screws being detached from the
LED module.
[0013] FIG. 3 is a view similar to FIG. 2, but one of the two
screws being screwed into the LED module and the support being
removed.
[0014] FIG. 4 is a view similar to FIG. 3, but configurations of
the two screws being varied.
DETAILED DESCRIPTION OF THE INVENTION
[0015] FIG. 1 is a top view of an LED module 10 fixed on a support
20 via a pair of screws 30 according to an embodiment of a method
to which the present invention is directed. The LED module 10
comprises a rectangular printed circuit board 12 and a plurality of
LEDs 14 uniformly arranged thereon.
[0016] Also referring to FIG. 2, the printed circuit board 12
constitutes a substrate 120 and a plurality of layers 122, 124
formed thereon. A pair of straight through holes 126 are defined
through the printed circuit board 12 between the LEDs 14, accepting
insertion of the screws 30 thereinto, thus engagingly attaching the
LED module 10 on the support 20. The substrate 120 is substantially
made of heat conducting material such as copper, aluminum or an
alloy thereof. The plurality of layers 122, 124 comprises a first
insulating layer 122, an electrically conductive layer (not shown),
and a second insulating layer 124 sequentially plated on the
substrate 120. A thickness of the substrate 120 is about 1.5 mm,
and a total thickness of the three layers 122, 124 approximately
0.1 mm, exaggerated in FIGS. 2-4. The first insulating layer 122
covers an overall top face of the substrate 120, thereby completely
insulating the electrically conductive layer from the substrate
120. The electrically conductive layer is patterned on the first
insulating layer 122 according to positioning of the LEDs 14,
avoiding the through holes 126. The electrically conductive layer
directly connects electrode leads (not shown) of the LEDs 14,
transferring current from a power source (not shown) thereto. The
second insulating layer 124 is formed on an outermost side of the
printed circuit board 12, preventing the electrically conductive
layer from coming in contact with other electrical terminals (not
shown). Since no electrically conductive layer is disposed adjacent
to the through holes 126, the second insulating layer 124 directly
joins the first insulating layer 122 in these locations as shown in
FIGS. 2-4.
[0017] Each screw 30 is integrally of metal, consisting of a head
32 and a pole 34 extending downwardly from a bottom face thereof.
The head 32 has a portion recessed downwardly in a top face
thereof, to thereby define two crossed slots 38 (as viewed in FIG.
1). A plurality of teeth 36 protrudes downwardly from the bottom
face of the head 32 and surrounds a top end of the pole 34. Each
tooth 36 is triangular with a relatively sharp extremity end
providing scraping capability if required. A plurality of spiral
threads (not shown) around a circumferential face of the pole 34
for engaging internal threads in holes (not shown) in the support
20, thus interferingly securing the LED module 10 onto the support
20.
[0018] Also with reference to FIG. 3, during mounting of the LED
module 10 onto the support 20, the screws 30 are prepared for ready
insertion through the through holes 126 in the printed circuit
board 12 with the teeth 36 thereof abutting a top face of the
second insulating layer 124 of the printed circuit board 12. As
rotation of each screw 30 generates downward progress toward the
support 20, the teeth 36 of the screws 30 scrape annular areas of
the second insulating layer 124 and the first insulating layer 122
of the printed circuit board 12 surrounding each through hole 126.
Until the teeth 36 reach the top face of the substrate 120, an
annular part of the top face of the substrate 120 surrounding each
through hole 126 is substantially exposed. Meanwhile, rigidity of
the substrate 120 prevents the ends of the teeth 36 from
penetrating deeply into the substrate 120, and the screws 30 are
impeded from further downward motion. At this time, the heads 32 of
the screws 30 project out of the second insulating layer 124 to
establish electrical connection with the top face of the second
insulating layer 124, and the poles 34 of the screws 30 are
threaded in the support 20, firmly attaching the LED module 10 to
the support 20.
[0019] As a result of the removal of annular areas of the first
insulating layer 122 and the second insulating layer 124 near the
screws 30 from the substrate 120, the head 32 of the screw 30 can
directly contact the substrate 120 and make electrical connection
with the top face of the second insulating layer 124 of the printed
circuit board 12. Static electricity generated on the top face of
the second insulating layer 124 is conducted via the screws 30 to
the substrate 120 which has been grounded beforehand, such that
malfunction of or damage to the LEDs 14 due to electrostatic
discharge is avoided.
[0020] Further, to ensure that the annular areas of the first and
second insulating layers 122, 124 surrounding the through holes 126
can be completely cleared, the screws 30 can be continuously
rotated and thereby impelled downward to scrape a top portion of
the substrate 120 under a large force, after engaging the top face
of the substrate 120. Thickness of material scraped off the
substrate 120 is commensurate with the force available, preferably,
in the present embodiment, such thickness is about 0.2 mm.
[0021] Alternatively, the screws 30 can be replaced by other
elements as long as the same function is accomplished. One among
such elements is shown in FIG. 4, which shows a fastening assembly
30a replacing the prior integrally formed screw 30. The fastening
assembly 30a comprises a screw (not labeled) which has a head 32a,
a pole 34a extending downwardly from a bottom face of the head 32a,
and a metal annulus 31a detachably sleeved on the pole 34a of the
screw. The annulus 31a has a circumference coincidental with that
of the head 32a of the screw. A plurality of teeth 36a projects
downwardly from the bottom face of the annulus 31a. The teeth 36a
are set to perform the same function as the teeth 36 of the
original screws 30, i.e., scraping annular areas of the first and
second insulating layers 122, 124 off the substrate 120 of the
printed circuit board 12. Note that the screw and the annulus 31a
of the fastening assembly 30a actually equal two corresponding
separated parts of the prior screw 30, respectively.
[0022] The above described processes of mounting the LED module 10
on the support 20 can also be summarized as providing a support 20,
an LED module 10 having a printed circuit board 12 and a plurality
of LEDs 14 mounted on the printed circuit board 12, and two
screws/fastening assemblies 30, 30a with teeth 36, 36a formed
therefrom, extending the screws/fastening assemblies 30, 30a
through the printed circuit board 12 of the LED module 10 and into
the support 20, screwing the screws/fastening assemblies 30, 30a
toward the support 20 to cause the teeth 36, 36a of the
screws/fastening assemblies 30, 30a to scrape annular areas of
insulating layers 122, 124 of the printed circuit board 12 of the
LED module 10 until a metal substrate 120 of the printed circuit
board 12 is exposed, and continuing screwing the screws/fastening
assemblies 30, 30a to scrapingly remove a top portion of the metal
substrate 120 having a thickness of about 0.2 mm.
[0023] In addition, the present invention further provides another
method for mounting the LED module 10 on the support 20 which can
equally ensure prevention of electrostatic accumulation on the LED
module 10, comprising providing a support 20, an LED module 10
having a printed circuit board 12 and a plurality of LEDs 14
mounted on the printed circuit board 12, and a plurality of
screws/fastening assemblies 30, 30a , milling portions of the
printed circuit board 12 in areas surrounding through holes 126
thereof to thereby expose a top face of a metal substrate 120; and
extending the screws/fastening assemblies 30, 30a through the
through holes 126 of the printed circuit board 12 and into the
support 20 to bring heads 32, 32a of the screws/fastening
assemblies 30, 30a into physical contact with the top face of the
metal substrate 120.
[0024] It is to be noted that the screws/fastening assemblies 30,
30a used in the latter method eliminate the need for formation of
teeth 36, 36a thereon, since the printed circuit board 12 has been
previously milled to expose the top face of the metal substrate
120, such that removal of the first and second insulating layers
122, 124 of the printed circuit board 12 by scraping the printed
circuit board 12 with the toothed screws/fastening assemblies 30,
30a is accordingly omitted. As well, conventional screws can be
used in this method. As before, a top portion with a thickness of
about 0.2 mm is removed, albeit in this case by prior milling.
[0025] It is believed that the present invention and its advantages
will be understood from the foregoing description, and it will be
apparent that various changes may be made thereto without departing
from the spirit and scope of the invention or sacrificing all of
its material advantages, the examples hereinbefore described merely
being preferred or exemplary embodiments of the invention.
* * * * *